Properties of sugarcane bagasse-hydrated lime bio-based insulation materials

Sugarcane bagasse is one of the largest agricultural residues globally, yet its use in long-lived construction materials remains limited. This study investigates non-structural bio-based insulation composites produced from as-received sugarcane bagasse and hydrated lime. Composites were manufactured at varying lime-to-bagasse ratios and densities using pressing and cured under controlled relative humidity to assess carbonation effects. Mechanical, hygrothermal, phase, and microstructural properties were characterised using compressive testing, thermal conductivity, moisture buffering, X-ray diffraction, FTIR, and SEM. Compressive strengths of 0.14–0.38 MPa were achieved at densities of 330–510 kg/m³ , governed primarily by compaction rather than carbonation. Thermal conductivity ranged from 0.057 to 0.078 W/m·K, with moisture buffering rated “Excellent”. XRD showed limited lime carbonation after 90 days under all curing conditions. The results demonstrate that bagasse–lime composites are suitable for insulation applications, while challenging assumptions of near-complete carbonation in hydrated lime binders.